000
FXUS61 KCTP 130723
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
323 AM EDT FRI MAR 13 2015
.SYNOPSIS...
RAIN WILL OVERSPREAD THE WEST THIS EVENING AND THE REST OF THE
REGION TONIGHT. THE RAIN WILL TAPER OFF TO SHOWERS SATURDAY
MORNING. SUNDAY WILL FEATURE COLDER TEMPERATURES AND GUSTY WINDS
WITH RAIN AND SNOW SHOWERS OVER THE WESTERN ALLEGHENIES. WEAK HIGH
PRESSURE ON MONDAY WILL BE DISPLACED QUICKLY BY A COLD AIR WHICH
WILL SETTLE IN FOR MID-WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE UPPER RIDGE AXIS SHOULD STAY TO OUR WEST THROUGH THE EVENING
HOURS. RECENT GUIDANCE HAS BEEN CONSISTENT IN HOLDING OFF MEAS
RAIN UNTIL CLOSE TO SUNSET IN THE WEST...AND AFTER DARK IN THE
CENTRAL AND EAST. THE LOW SFC DEWPOINTS SUPPORT THIS IDEA AS
WELL. THERE WILL BE PATCHY MID CLOUDS TODAY...AND THE HIGH CLOUDS
WILL THICKEN UP QUICKLY THIS AFTERNOON. SOUTHERLY WINDS WILL
LIKELY FEEL BETTER THAN THE NORTH WIND OF THURSDAY...BUT THE
RESULTING TEMPS WILL BE VERY SIMILAR. WE WILL PROBABLY ADD A DEG
OR SO ONTO YESTERDAY/S MAXES WITH WEAK WARM ADVECTION BUT NOT MUCH
MORE DUE TO THE INCREASING CLOUDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THREAT FOR FZRA/SLEET TINY FOR THE NERN MTNS SO WILL CONTINUE TO
KEEP AWAY FROM A MENTION OF IT AT THIS POINT. CATG POPS ON ORDER
FOR ALL BUT THE FAR NRN TIER...WHERE THE NAM JUST BRUSHES THE NY
BORDER WITH PRECIP. OTHERWISE...A MODERATE RAINFALL EVENT IS IN
STORE FOR TONIGHT AND EARLY SATURDAY...BUT THE STEADY PRECIP
SHOULD EXIT TO THE EAST FAIRLY QUICKLY ON SAT WITH THE DEEPER SFC
LOW WELL TO THE NORTH AND FAST WRLY FLOW OVERHEAD. UPSLOPE AND
COLD ADVECTION ON SAT AFTN INTO SUNDAY MORNING WILL LIKELY RESULT
IN SCT SHRA/SN IN THE HIGHER ELEVATIONS OF THE WEST. QPF SEEMS
VERY CONSISTENT ACROSS THE BOARD WITH AROUND 1 INCH IN THE SRN
LAURELS AND AGAIN IN THE SERN COUNTIES. LESS PRECIP IS EXPECTED IN
THE CENTRAL MTNS AND EVEN LESS - PERHAPS ONLY A QUARTER OF AN INCH
NORTH OF I-80. SEE THE HYDRO SECTION FOR MORE INFO.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
1007MB SURFACE LOW TO THE NORTH MOVES EAST AND DEEPENS AS IT
SLIDES OFF NORTHERN NEW ENGLAND COAST. COLD AIR WRAPPING AROUND
THE BACKSIDE OF THE LOW WILL FAVOR LOWER DAYTIME TEMPERATURES WITH
UPSLOPE NW FLOW RAIN/SNOW SHOWERS PERSISTING OVER THE NRN AND WRN
ALLEGHENIES. WINDS WILL ALSO BECOME GUSTY WITH STRONG LLVL CAA AND
DECENT MIXING CONTRIBUTING TO TIGHT GRADIENT FLOW.
THE COOL DOWN BEHIND THIS SYSTEM FOR LATE WEEKEND SHOULD BE
BRIEF WITH 850MB TEMPS QUICKLY MODERATING BY EARLY MONDAY.
REINFORCING SHOT OF COLD AIR LIKELY FOR TUE. A SEASONABLY COOLER
PATTERN /WITH TEMPERATURES NEAR TO BELOW AVG/ SHOULD PREVAIL FROM
ST. PATRICK'S DAY INTO THE LAST FULL WEEK OF MARCH...WITH NAEFS
AND ECENS MEANS IN MUCH BETTER AGREEMENT DURING THE LAST COUPLE
MODEL CYCLES IN DEPICTING A WRN NOAM RIDGE/ERN TROUGH
CONFIGURATION OR +PNA TELECONNECTION.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE REGION WILL RESULT IN A NEAR CERTAINTY OF
VFR CONDS AND LGT WIND THROUGH EARLY THIS EVENING. LOW PRES
LIFTING OUT OF THE MISS VALLEY WILL SPREAD RAIN AND LOWERING CIGS
ACROSS THE REGION AFTER DARK TONIGHT. WIDESPREAD IFR/LIFR CONDS
APPEAR LIKELY LATE TONIGHT IN RAIN/LOW CIGS.
OUTLOOK...
SAT...RAIN/LOW CIGS LIKELY...MAINLY AM.
SUN-TUE...NO SIG WX EXPECTED.
&&
.HYDROLOGY...
FLOOD WATCH HAS BEEN POSTED FOR THE LAURELS WHERE AT LEAST AN INCH
OF RAIN IS EXPECTED OVER MOST OF SOMERSET CO. WHILE PRECIP SHOULD
TAPER OFF SIGNIFICANTLY BETWEEN JOHNSTOWN AND DUBOIS...THE HALF TO
THREE-QUARTERS OF AN INCH OF QPF THERE MAY LEAD TO SMALL STREAM
FLOODING WHEN ADDED TO THE SNOW MELT WHICH IS ON-GOING. ALSO
ON-GOING IS AN ICE JAM IN CENTRAL CLEARFIELD COUNTY. THIS ONE
INSTANCE MAY REPEAT ITSELF AS MANY OF THE SMALLER CREEKS ARE FULL
OF ICE AND THE ADDITIONAL RAIN MAY BE TOO MUCH TO KEEP THEM IN
THEIR BANKS.
A SECOND BULLSEYE OF ONE INCH RAINFALL IS FORESEEN IN THE LOWER
SUSQUEHANNA VALLEY. WHILE THE QPF IS SIMILAR TO THAT EXPECTED IN
THE LAURELS...THERE IS LESS/NO SNOW LEFT IN MANY LOCATIONS.
ALSO...THERE IS LESS ICE ON THE SMALLER WATERWAYS IN THE SE.
TEMPS ABOVE FREEZING FOR MOST OF THE TIME THESE PAST 4 DAYS HAS
MELTED LOTS OF THE ICE ON THE SMALLER CREEKS. HOWEVER...STREAMFLOWS
ACROSS SOUTH-CENTRAL/SOUTH-EASTERN PA ARE RUNNING WELL ABOVE
NORMAL FOR THIS TIME OF YEAR. LATER SHIFTS MAY NEED TO CONSIDER A
FLOOD WATCH FOR A WIDER AREA...PERHAPS EXTENDING ACROSS MOST OF
SRN PA. BUT FOR NOW WILL MENTION MINOR FLOOD RISK IN THE HWO FOR
MUCH OF THE AREA.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM THIS EVENING THROUGH SATURDAY EVENING FOR
PAZ017-024-033.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD
HYDROLOGY...DANGELO